problem with power supply to dc motors

[system]

hai

i'am a newbie to arduino and has very less knowledge in electronics

i want to control my remote car using arduino, so i removed the circuitry of my remote car leaving the motors( had attached the images of it )

i had read some basic tutorials on arduino and motors, i used l293d to control 2 motors and made the connections like

enable1,2 -- arduino pin 10
enable 3,4 -- arduino pin 11
input 1 -- arduino 8
input 2 -- arduino 9
input 3 -- arduino 4
input 4 -- arduino 2

in order to check the simple motion of back wheels i uploaded the following code
i connected output 3 and 4 to the motor wires of back wheels of my car

int enable34=11;
int input3=4;
int input4=2;



void setup()
{
  pinMode(enable34,INPUT);
  pinMode(input3,OUTPUT);
  pinMode(input4,OUTPUT);
}

void loop()
{
  
  
  analogWrite(enable34,255);
  digitalWrite(input3,HIGH);
  digitalWrite(input4,LOW);
  delay(3000);
  
  digitalWrite(input4,HIGH); delay(3000);
  
}

when i connected USB cable to power arduino and vcc pins(8,16) of l293d to 5v of arduino the car moves

when i connected USB cable to arduino and 8 th pin of l293d to 9v battery and 16 th pin of l293 d to 5v of arduino the car is not moving

when i connect arduino to 9v battery and 8 th pin of l293d to 9v battery and 16 th pin of l293 d to 5v of arduino the car is not moving but when i lift it up the wheels are moving too slow and some times i had to initialize the motion

iam totally worried about this
i am thinking that the battery's could not supply the sufficient power to run the motor
but the usb port is providing the sufficient !

as i told earlier i had very less knowledge in electronics please help me with a way to provide an alternate power supply to run my car with out the usb

iam providing the necessary photographs of my project

thanks in advance

[jackwp]

It may be as you suggested, your 9 volt battery is not supplying enough power (it may be depleted). Use a volt meter to check the voltage of the 9 volt line, while the motor is trying to run.
What voltage does the motors need. If they worked from the usb power, then 5 volts makes them run.
I would replace the 9 volt battery with 4 AA batteries of high capacity (3000 mah or more).

[system]

thank you very much sir...

i have tried what you said 4 AA batteries when connected directly to motor car runs with high speed

i used 6f22 9v battery to power arduino and 4 AA batteries as input to Vss(pin 8) of l293d , Now car the moves with less speed compared to the earlier case

i have read that there will be a voltage drop in l293d ,are there any solutions to overcome this problem

is using 6f22 9v battery to power arduino is efficient or not ?

thanks in advance

[jackwp]

If the 4 AA batteries, through the l293d is not enough speed, they try using 6 AA batteries.

The arduino can run ok with 9 volts on the Vin. It would be more efficient with about 7 volts tho. If you wanted to drop it a bit, you could add a couple diodes in series with the 9 volt battery.

[system]

Thanq sir. .
I want to know whether 6f22 9V battery can sufficiently power arduino

[jackwp]

I am not familiar with a 6f22 9V battery. But, 9 volts is plenty to power an arduino. If it stays up to 9 volts you are in good shape.
But most small 9 volt batteries, will discharge pretty quickly. So, for a while (maybe a several minutes or hours, depending on the power draw) it will work great. But when the battery gets depleted, putting out less than 4 or 5 volts, you will have a problem.

EDIT: Check 9v battery current | Electronics Forum (Circuits, Projects and Microcontrollers) for info on batteries.

[MarkT]

parimi:
i have read that there will be a voltage drop in l293d ,are there any solutions to overcome this problem

No solutions other than to avoid H-bridge chips using darlington output stages (L293D & L298 for instance)

• that is the reason for the 2.5V or so voltage lose.

MOSFET H-bridges may perform far better, but you have to check the figures to work out the losses for a given load
current.